Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if you
knew exactly where the exit hole would be? Getting it on a mortar course
would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps, but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

"The Medway Handyman" wrote in message
.uk...
Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if
you
knew exactly where the exit hole would be? Getting it on a mortar course
would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps,
but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257



How deep do those metal detectors go? a square 2" metal plate held against
the wall outside/inside and the metal detector operated in the vicinity? of
the plate might do it?

The Medway Handyman wrote:

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps, but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.

Hmm. You can transfer a level using a transparent pipe filled with water
(wherever it goes in between, the water levels at the ends will be
equal). A bit fiddly to set up, but perhaps there's scope for using the
underlying principle with some sort of magic box at one or both ends?

Pete

"George" wrote in message
.uk...

"The Medway Handyman" wrote in message
.uk...
Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm
pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if
you
knew exactly where the exit hole would be? Getting it on a mortar course
would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps,
but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257



How deep do those metal detectors go? a square 2" metal plate held against
the wall outside/inside and the metal detector operated in the vicinity?
of
the plate might do it?



Drill from the outside using a small but long bit, one designed for alarm
cable. That will not cause much damage to the wall if you take it easy.
Once the hole is where you want it, drill from the inside out with the
larger bit. Then it doesn't look nasty with bits of plaster and brick
popping out.
I have not see a device such as the one described. Go and patent something.

"john" wrote in message

How deep do those metal detectors go? a square 2" metal plate held
against
the wall outside/inside and the metal detector operated in the vicinity?
of
the plate might do it?



Drill from the outside using a small but long bit, one designed for alarm
cable. That will not cause much damage to the wall if you take it easy.
Once the hole is where you want it, drill from the inside out with the
larger bit. Then it doesn't look nasty with bits of plaster and brick
popping out.
I have not see a device such as the one described. Go and patent
something.



If you're drilling from outside in and have an idea of where the hole might
be?, get someone with a piece of 12"x3/8" square wood to hold it against the
inside wall firmly as this will stop the plaster shattering around the
drilled hole.

Its a bit lie drilling a hole in wood...you put a piece of scrap wood
underneath to stop the wood splintering on the other side.

"The Medway Handyman" wrote in message

I'd pay good money for a device that could accurately do that.



There ya go do you have the money? and a lighter.
http://www.fluke.co.uk/comx/portal_ti.aspx?locale=uken

In article ,
"The Medway Handyman" writes:
Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if you
knew exactly where the exit hole would be? Getting it on a mortar course
would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps, but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.

They had a similar problem making sure the two ends of the
Channel Tunnel would meet in the middle. Until the tunnel
actually broke through, it was not even known how different
the official "sea level" height was between Great Britain
and Continental Europe. Once the tunnel was there, it could
be measured of course, and separate teams from the UK and
France both did so in parallel.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:
They had a similar problem making sure the two ends of the
Channel Tunnel would meet in the middle. Until the tunnel
actually broke through, it was not even known how different
the official "sea level" height was between Great Britain
and Continental Europe. Once the tunnel was there, it could
be measured of course, and separate teams from the UK and
France both did so in parallel.


That's a helluva long water level.


--
Ian White

"The Medway Handyman" wrote in message
.uk...
I drill from the inside to the outside usually. Wouldn't it be great if
you knew exactly where the exit hole would be? Getting it on a mortar
course would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps,
but its difficult if not impossible sometimes.

There just is no way it can be done with the level of accuracy needed to get
two separate holes to be a perfect meet in the middle - I too have thought
long and hard over the years for a solution to the problem. Even if you can
manage it good enough to mark two perfectly back to back marks on either
side of the wall, there is still no certainty the holes will meet up in
practise - unless you can keep the drill square and level. I just start with
as thin a drill as possible to minimise the damage on the exit side and make
a decision on which side to drill from based upon the practicalities each
time. If there are useable points of reference on both sides of the wall,
like door and window frames, you can get a useful idea of the exit point by
measurement.

The best I can come up with assuming two people on the job is -
As someone else suggested, a water level can be used to get an accurate
height reference on both sides of the wall. Add to that a couple of laser
pointers mounted on a rigid bracket, such that the bracket can be passed
through a door or window opening with the lasers shining a line along either
side of the wall. Where the laser lines cross the water level marks, is
where you drill from each side. A bubble level might be useful fixed to the
above laser bracket, to ensure it is level - plus some means to get it
square against the wall.

Pete Verdon wrote:
The Medway Handyman wrote:

In these days of straight line lasers, metal detectors etc, would it
be possible to design a gadget to pinpoint the exit hole? Measuring
helps, but its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.

Hmm. You can transfer a level using a transparent pipe filled with
water (wherever it goes in between, the water levels at the ends will
be equal). A bit fiddly to set up, but perhaps there's scope for
using the underlying principle with some sort of magic box at one or
both ends?

Good thinking Pete. Thats half the problem solved - getting the right
horizontal - I have a proper water level (used for decking).

Now if I can just figure out the vertical....


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

john wrote:


Drill from the outside using a small but long bit, one designed for
alarm cable. That will not cause much damage to the wall if you take
it easy. Once the hole is where you want it, drill from the inside
out with the larger bit. Then it doesn't look nasty with bits of
plaster and brick popping out.

But if you drill from the outside you can never be sure where its going to
come out inside. Thats the problem.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

On Sun, 13 Jan 2008 08:46:55 +0000 (UTC), wrote:
Thus spake Pete Verdon d) unto the assembled multitudes:
The Medway Handyman wrote:

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps, but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.

Hmm. You can transfer a level using a transparent pipe filled with water
(wherever it goes in between, the water levels at the ends will be
equal). A bit fiddly to set up, but perhaps there's scope for using the
underlying principle with some sort of magic box at one or both ends?

Fine for getting the correct vertical position, but useless for your
horizontal measurement which will be just as important.

But if all you want is to hit a mortar line to prevent having to make good,
(from OP) then don't you just need to know the vertical position presuming
of course that the bricks were laid horizontally.
You do have to make sure the hole you drill is level :-)

--
.................................................. .........................
.. never trust a man who, when left alone ...... Pete Lynch .
.. in a room with a tea cosy ...... Marlow, England .
.. doesn't try it on (Billy Connolly) .....................................

In article k The Medway
Handyman wrote:

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? *Measuring helps,
but its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.

ISTR seeing such a device in a Screwfix catalogue a few years ago but
there's no sign of it now. I think it involved attaching an ultrasonic
source to the point where you wanted the hole to emerge and using a sensor
to search for the strongest signal on the other side but I can't see any
sign of it in the present catalogue or find it anywhere else with Google.
No idea how accurate it was and I doubt if it'd have worked across a cavity
wall.

--
Mike Clarke

Andrew Gabriel wrote:
In article ,
"The Medway Handyman" writes:
Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if you
knew exactly where the exit hole would be? Getting it on a mortar course
would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps, but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.

They had a similar problem making sure the two ends of the
Channel Tunnel would meet in the middle.

Yes, I remember seeing a newspaper cartoon at the time where they'd just
broken throught, but the workers were scratching their heads as they'd
managed to mate up the northernmost UK tunnel with the southernmost
French tunnel (well, sorry, it was funnier in picture form).

Until the tunnel
actually broke through, it was not even known how different
the official "sea level" height was between Great Britain
and Continental Europe. Once the tunnel was there, it could
be measured of course, and separate teams from the UK and
France both did so in parallel.

And... what was the answer?!

David

"The Medway Handyman" wrote in message
.uk...
I'd pay good money for a device that could accurately do that.


can it really be that hard?
a transmitter probe
and a receiver/indicator
like you say, in this day and age, it can;t be that hard.
--
Vass

The Medway Handyman wrote:
Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if you
knew exactly where the exit hole would be? Getting it on a mortar course
would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps, but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.



I've been thinking of a way to do this for a while. I need to drill a
hole through a cellar wall to meet an external drain, and have yet to
find a way to do it accurately. The answer may be magnets. The following
is an extract from a US patent no longer available on the web:

-----

Currently, the problem of locating a potential drill bit exit hole on
the blind side of the building structure may be done with careful
measurements and visual estimation of where the through-hole will enter
and exit the building structure. However, visual estimation is often
inaccurate and taking measurements is sometimes tedious. Furthermore,
both of these methods are time consuming.

Thus, there is a need for a method and apparatus for through-hole
placement in a building structure that addresses the above described
drawbacks.

SUMMARY

According to exemplary embodiments, the present invention provides a
method and apparatus for through-hole placement used in conjunction with
routing wires through partition walls including walls, floors, and
ceilings of a building structure.

According to exemplary embodiments, the present invention provides a
method and apparatus for positively locating both ends defining a
potential through-hole before drilling the same.

According to one aspect, an apparatus for determining a location of a
through-hole in a building structure includes a magnet disposed at a
first location on a first side of the building structure. The first
location is selected on the first side of the building structure that
will define a first opening of the through-hole. A magnetic pointer is
disposed at a second location on a second side opposite the first side
in magnetic communication with the magnet. The magnetic pointer is
configured to point to the magnet indicating a direction of the
through-hole in the building structure defined by a second opening on
the second side to the first opening on the first side when the
through-hole is drilled.

Another aspect is a method for creating a through-hole in a building
structure includes selecting a first location on a first side of the
building structure that will define a first opening of the through-hole;
disposing a magnet at the first location; selecting a second location on
a second side opposite the first side via a magnetic pointer
magnetically pointing to the magnet; and drilling the through-hole from
the second side through the building structure in a direction indicated
by the magnetic pointer creating the through-hole defined by the first
and second openings on the first and second sides, respectively.

------

No idea if this would work, but it seems there is a need for such a device.

Rob

"Rob" wrote in message

I've been thinking of a way to do this for a while. I need to drill a
hole through a cellar wall to meet an external drain, and have yet to
find a way to do it accurately. The answer may be magnets. The following
is an extract from a US patent no longer available on the web:


This wouldn't work with a standard magnet of decent enough size to carry
around with you on jobs.

So whats needed is an electromagnet with a compass needle as the pinpointer
source ie you secure the EM to the wall and go the other side of the wall
and use the compass near to the EM till the Compasses needle is at its
strongest pull.

"The Medway Handyman" wrote in message
.uk...
Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if
you knew exactly where the exit hole would be? Getting it on a mortar
course would mean no breakout to make good.

So, the question; How could you achieve this?

I use a 300mm x 6mm drill to make a pilot hole. With a bit of practice, it
is not too difficult to use a large mirror to see you are holding it level.
I then follow the pilot hole in from each side, towards the cavity.

Colin Bignell

nightjar cpb@ wrote:
"The Medway Handyman" wrote in message
.uk...

Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if
you knew exactly where the exit hole would be? Getting it on a mortar
course would mean no breakout to make good.

So, the question; How could you achieve this?


I use a 300mm x 6mm drill to make a pilot hole. With a bit of practice, it
is not too difficult to use a large mirror to see you are holding it level.
I then follow the pilot hole in from each side, towards the cavity.

When drilling for cables, I always drill from outside and angle the
drill upwards. This prevents any water ingress. Using the final size
drill, I then drill from the inside through the inner wall, reversing
the angle and then do the same from the outside using the original
angle. I have only ever managed not to meet up in a straight line once.
I cured that by opening up the inner wall until I got a straight line
and then made good with plaster.

Pipes should be easy. Drill from the outside, by either getting some one
to sight you level in the vertical plane and use a small square in the
horizontal, so that you can see that it is parallel from above. Open up
to full size as above.

Dave

"Andrew Gabriel" wrote in message
...
In article ,
"The Medway Handyman" writes:
Last week I had three occasions where I had to drill holes through double
skin brick or brick/block walls. Twice for cables & once for a 15mm
pipe.
It got me thinking - sorry chaps.

No problem drilling the holes, but getting the alignment right would be a
big help.

I drill from the inside to the outside usually. Wouldn't it be great if
you
knew exactly where the exit hole would be? Getting it on a mortar course
would mean no breakout to make good.

So, the question; How could you achieve this?

In these days of straight line lasers, metal detectors etc, would it be
possible to design a gadget to pinpoint the exit hole? Measuring helps,
but
its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.

They had a similar problem making sure the two ends of the
Channel Tunnel would meet in the middle. Until the tunnel
actually broke through, it was not even known how different
the official "sea level" height was between Great Britain
and Continental Europe. Once the tunnel was there, it could
be measured of course, and separate teams from the UK and
France both did so in parallel.

--
Andrew Gabriel

They were not that accurate. The centre points of the tunnels were 358mm
horizontally and 58mm vertically out of line with each other.
Mind you, I would expect two 13 mile long masonry drills bit to wander a
little as you use them:-)

Adam

"Andrew Gabriel" wrote in message

They had a similar problem making sure the two ends of the
Channel Tunnel would meet in the middle. Until the tunnel
actually broke through, it was not even known how different
the official "sea level" height was between Great Britain
and Continental Europe. Once the tunnel was there, it could
be measured of course, and separate teams from the UK and
France both did so in parallel.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]


Did they ever find any artifacts/old coins ect,when they dug out the inland
headers out? I bet ya the archeologist where there all the way sifting
through the dirt. :-)

The Medway Handyman wrote:
Pete Verdon wrote:
The Medway Handyman wrote:

In these days of straight line lasers, metal detectors etc, would it
be possible to design a gadget to pinpoint the exit hole? Measuring
helps, but its difficult if not impossible sometimes.

I'd pay good money for a device that could accurately do that.
Hmm. You can transfer a level using a transparent pipe filled with
water (wherever it goes in between, the water levels at the ends will
be equal). A bit fiddly to set up, but perhaps there's scope for
using the underlying principle with some sort of magic box at one or
both ends?

Good thinking Pete. Thats half the problem solved - getting the right
horizontal - I have a proper water level (used for decking).

Now if I can just figure out the vertical....

Problem is that on many holes you want a slight downwards slope toward
the outside to ensure that water can not be tracked through.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Yep. Agree with that. Drill slightly downwards towards France.

In article ,
"ARWadworth" writes:

"Andrew Gabriel" wrote in message
...
They had a similar problem making sure the two ends of the
Channel Tunnel would meet in the middle. Until the tunnel
actually broke through, it was not even known how different
the official "sea level" height was between Great Britain
and Continental Europe. Once the tunnel was there, it could
be measured of course, and separate teams from the UK and
France both did so in parallel.

They were not that accurate. The centre points of the tunnels were 358mm
horizontally and 58mm vertically out of line with each other.
Mind you, I would expect two 13 mile long masonry drills bit to wander a
little as you use them:-)

Thought I noticed a bump in the middle ;-)

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Andrew Gabriel" wrote in message
...
In article ,
"ARWadworth" writes:

"Andrew Gabriel" wrote in message
...
They had a similar problem making sure the two ends of the
Channel Tunnel would meet in the middle. Until the tunnel
actually broke through, it was not even known how different
the official "sea level" height was between Great Britain
and Continental Europe. Once the tunnel was there, it could
be measured of course, and separate teams from the UK and
France both did so in parallel.

They were not that accurate. The centre points of the tunnels were 358mm
horizontally and 58mm vertically out of line with each other.
Mind you, I would expect two 13 mile long masonry drills bit to wander a
little as you use them:-)

Thought I noticed a bump in the middle ;-)


In the early 70s my Dad had to make a calculation about joining two coal
mines (Dodworth and Redbrook). He had to do it using triangulation with no
lazers, GPS etc. The biggest problems were the plumblines that were dropped
down the mine shafts. These only worked with the mine ventilators turned off
and it needed 2 days for the draughts to stop. The work/calculations were
done over Christmas and he managed to get the shafts to line up to within 12
inches of each other over a 600 yard distance that crossed a fault line.

I found his old work papers in his loft this Christmas and he has said I can
keep them. They will have a good home. The plumb dropped down the shaft was
done by a machine but took 3 men to lift it onto the machine! The concrete
post that the NCB installed for triangular recording is still in the field
full of cows some 35 years later.

Adam

George wrote:
So whats needed is an electromagnet with a compass needle as the pinpointer
source ie you secure the EM to the wall and go the other side of the wall
and use the compass near to the EM till the Compasses needle is at its
strongest pull.

I'm sure William Scoresby proposed just such a system in 1820.

--
JGH

In article ,
says...
So, the question; How could you achieve this?

I remember a friend's mum doing this when I was about 13. She was
fitting a new radiator and didn't have a drill bit long enough to reach
from the 18th century bit of the house to the modern bit, so she
carefully measured it round 8' or so through two doorways and got it
bang on. A 20mm hole and the 15mm pipe slid through perfectly.

--
Skipweasel.
Never knowingly understood.

"jgharston" wrote in message
...
George wrote:
So whats needed is an electromagnet with a compass needle as the
pinpointer
source ie you secure the EM to the wall and go the other side of the
wall
and use the compass near to the EM till the Compasses needle is at its
strongest pull.

I'm sure William Scoresby proposed just such a system in 1820.

--
JGH


Yes,but he wasn't interested in drilling through walls accuratly.

On Sun, 13 Jan 2008 15:05:36 GMT, George wrote:

This wouldn't work with a standard magnet of decent enough size to carry
around with you on jobs.

I wouldn't be so sure with some of the Neodymium magnets that you can get
these days. One of them and a sensitive indicator (compass) could well
work.

Place magnet at wanted exit point with a pole firing into wall. Other side
of wall move compass horizontally along wall until need is at 90 deg to
wall mark that. Move compass vertically through previous mark untill need
is at 90 deg again, mark. Both horizontal and vertical alignments.

I'm not sure what effect metal ties, pipes or near by radiators would have
on the accuracy of the above method. It might be worth doing three
horizontal and vertical "scans" to see if the three marks make a
straight(ish) line.

I don't have a Neodymium magnet to play with.

--
Cheers
Dave. pam is missing e-mail